1. Technical Field
This invention relates to a supercapacitor and a manufacturing method thereof.
2. Description of the Related Art
Technologies from the various fields have been actively combined together, with customer's strong desire for the realization of small form factor and ubiquitous.
For the realization of this technical desire, the improvement in electricity, electron, communication, electronic material and parts progresses separately or combinatively in various fields, based on research and development of technical improvement and the market prospect.
In these various technologies, especially the manifestation of high-tech for the electronic products of small form factor and actualization of electronic parts using up-to-date materials are possible, for example, the latest digital IC (integrated circuit) chip can provide the power stably as the frequency becomes higher and voltage becomes lower.
Also the need for low impedance decoupling capacitor is getting important to remove switching noise.
There are lots of reports about the technology making a capacitor on IC because a decoupling capacitor can lower impedance as closer to the IC chip.
Also the interest is getting heighten for the electrochemistry capacitor knows as supercapacitor, as the development is growing for electric transports such as electric car, needed strong power in a short time.
With the development of supercapacitor, an attempt to use a conductive polymer as an electrode is increasing. Among many conductive polymers, especially a study for polypyrrole (PPy) is vigorous. PPy is used importantly as the electrode of supercapacitor due to its porosity, good electrical conductivity and fast doping-dedoping properties. Also it is important to make PPy as thin and equally to maximize the ion diffusion.
And to increase an amount of movement of ions, the wide surface is needed because electrochemical processing is performed on the surface of electrode. Nano sized structure with wide surface and good porosity is very suitable for the electrode of supercapacitor.
Recently many studies are in progress using a complex of PPy and CTN on account of wide surface and good porosity of CNT (carbon nano tube). It is reported that a nano sized electrode using PPy and CNT has better capacitance than an existing PPy film. But making CNT dispersion and PPy/CNT electrode is difficult due to its attribute of CNT.
Also there is a problem since the resistance increases when a nano sized conductive polymer is polymerized to an electrode.